Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Variable Interest Entity [Line Items]
Operating Revenues	$ 3,755	$ 2,313
Operation and Maintenance	743	794
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues	128	123
Operation and Maintenance	128	$ 123
Ocean Wind JV Holdco
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 223		$ 225